1ES 2344+514 PDF Print
1ES 2344+514 SED
Spectral energy distribution of 1ES 2344+514. The high flux spectrum (triangles) are from VERITAS data on December 7, 2007 and Swift UVOT and XRT data on December 8, 2007. The time-averaged VERITAS spectrum and near-average flux level X-ray spectrum from Swift XRT and RXTE PCA data on January 1, 2008 are represented by circles. Non-contemporaneous VHE gamma-ray spectra are shown from MAGIC data in August to December 2005 (open squares) and from Whipple 10 m data on the flare night of December 20, 1995 (open triangles). All VHE gamma-ray spectra are corrected for absorption by the extragalactic background light (Franceschini et al. 2008). Archival millimeter fluxes (open diamonds) are from SCUBA data (Stevens & Gear 1999). The broadband curves are from synchrotron self-Compton (SSC) modeling to the contemporaneous data (Krawczynski et al. 2004).

1ES 2344+514


1ES 2344+514 is a nearby (z = 0.044) blazar , and was discovered at very high energy (VHE) gamma-rays energies ( >350 GeV) by the Whipple 10 m telescope during a 1 day flare on December 20, 1995. Blazars are active galactic nuclei (AGN) with a relativistic plasma jet oriented close to the line of sight. These objects exhibit rapid variability and have broadband spectral energy distributions (SEDs) characterized, in a νFν representation, by a synchrotron component extending from radio to X-ray frequencies, and a second component peaking at gamma-ray frequencies due to either inverse-Compton radiation or from hadronic processes.

VERITAS observed 1ES 2344+514 for 18 hours spread over 37 nights between October 4, 2007 and January 11, 2008. The total VERITAS signal has a statistical significance of >20 sigma. A strong VHE gamma-ray flare on December 7, 2007 was measured at F(>300 GeV) = (6.76 ± 0.62) * 10-11 cm-2 s1, corresponding to 48% of the Crab Nebula flux. Excluding this flaring episode, nightly variability at lower fluxes was observed with a time-averaged mean of 7.6% of the Crab Nebula flux.

During the full period of VERITAS observations contemporaneous X-ray and UV data were taken with Swift and RXTE. Variability by a factor of ~7 is evident in the 2–10 keV flux between nightly observations. On December 8, 2007 the highest ever observed X-ray flux from 1ES 2344+514 was measured by Swift XRT. Evidence for a correlation between the X-ray flux and VHE gamma-ray flux on nightly time-scales is indicated with a Pearson correlation coefficient of r = 0.60 ± 0.11. Contemporanous spectral energy distributions (SEDs) of 1ES 2344+514 are presented for two distinct flux states. A one-zone synchrotron self-Compton (SSC) model describes both SEDs well.

For more information on the science of this object please contact Jeffrey Grube .


Last Updated on Thursday, 27 May 2010 02:29

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